Who is at high risk for lung cancer? Population-level and individual-level perspectives.

Lung cancer is the leading cause of cancer death in the world. However, there is large geographic variation internationally and within nations. Despite the fact that many causes of lung cancer have been established, cigarette smoking is the principal cause. Accounting for historical prevalence of cigarette smoking is a useful predictor of the lung cancer burden in most populations. The populations at high present risk of lung cancer can usually be predicted based on historical patterns of the prevalence of cigarette smoking, and the high-risk populations of the future can be predicted based on the current prevalence of cigarette smoking. Lung cancer rates are consistently higher among men than women and are particularly high among African American men and among those of lower socioeconomic status. At the individual level, some segments of the population (e.g., African Americans, females) have been hypothesized to have greater susceptibility to lung cancer for a given degree of cigarette smoking. Common variants in genes that encode for enzymes involved in carcinogen metabolism and detoxification and in repairing DNA damage are likely to be important determinants of interindividual susceptibility to smoking-caused lung carcinogenesis. Many lung cancer risk factors have been identified, but active cigarette smoking is the predominant cause of lung cancer and the principal marker of both high-risk populations and high-risk individuals. In the absence of cigarette smoking, lung cancer would be a rare disease. Strategies that effectively prevent youths from starting to smoke and that promote cessation among dependent smokers can transform populations from high risk to low risk.